php implementation of a image-verification system by Chirag Mehta

Block Spam Bots With Free CAPTCHA Service

Posted by timothy on Wednesday November 12, @12:55PM
from the screwtape-and-pals-shriek dept.

Chirag Mehta writes “I just released a freeware service called BotBlock (barebones demo) that lets site owners copy/paste a few lines of PHP code and insert a CAPTCHA image-verification system into any web form. The amount of form spamming by bots is on a rise. While remedies exist for MT blogs, a more efficient solution is to use image-verification or text-identification. Used for a while by sites like Yahoo! (scroll to bottom), Hotmail and patented in 2001 by AltaVista, CAPTCHAs are now being used more widely. PARC also came up with two algorithms Baffletext and Pessimal Print. The technology always existed, but until now required the site owners to install image libraries and understand how to generate images that cannot be OCR’ed. With BotBlock it is like inserting a page counter.”

http://developers.slashdot.org/article.pl?sid=03/11/12/1715232

Posted in Technology Review.

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